Their discovery focuses on the Antarctic circumpolar current, which picks up and cools water that descends from warmer latitudes in the Atlantic, Indian and Pacific oceans.

The scientists decided to use a natural plume of helium, disgorged from a submarine volcano in the East Pacific, to trace the current.

They found an extraordinary mixing of the current in the Southwestern Atlantic at the Scotia Sea, a triangular-shaped area between Tierra del Fuego and the Antarctic peninsula.

The Scotia Sea is notorious for the storms that lash its surface, but what surprised the researchers was the violent twisting of the layers underneath.

The eddy cuts across isopycnals, layers of the sea of different densities, and effectively acts as a 'short circuit' in the Antarctic circumpolar current.

This allows cold waters that sink to the bottom to return to the surface quicker than anyone thought.

The scientists think the rough topography of the sea bed allows this to happen.

A better understanding of ocean currents will mean scientists can get an idea as to how swiftly surface warmth will start to heat up lower levels and whether the carbon dioxide, absorbed by algae, is sequestered at the ocean bottom or in contrast churned back up to the surface.